Connecting various components together is a step in many manufacturing processes and numerous systems and methods exist for joining multiple components together. The term “joint” refers to the point or location between at least two components coupled together. For example, multiple elements may be coupled together at a joint through the use of fasteners (e.g., screws, bolts, nails, straps, etc), interlocking pieces, welding techniques, and/or adhesive compositions. Each of these methods for joining components together has its advantages and disadvantages depending on various factors (such as the size, weight, and composition of the components and the humidity, temperature, and pressure of the environment), and each type of coupling has a corresponding strength rating. The strength of a coupling is ascertained by testing the joined components to determine if the joint is sufficiently strong to withstand required load thresholds and if the joint has the durability to hold up over a useful lifecycle. These joint tests, and the corresponding strength ratings, can be important for the safety of users that operate, exploit, interact with, or otherwise use end-products with joints and coupled components.
Generally, the procedures and systems for testing joints involve controllably increasing a load on a joint or subjecting the joint to repeated load cycles, and determining if the joint can sustain the proof load, if defects occur, and/or if the joint reaches a failure point. For example, joints can be tested to determine the load range in which the joint is elastic (i.e., the range in which the joint does not suffer any permanent damage or distortion), the load range in which the joint is plastic (i.e., the range in which the joint still is capable of sustaining a load but permanent damage and distortion has occurred, resulting in permanent defects), and the load range in which the joint fails.
Conventional strength tests are generally performed ex situ and usually include applying shear, compression, and/or tensile type forces to the joint. For example, when conventionally testing an adhesive coupling (“bonded joint”), as may be found in a frame of an aircraft, the joint is often removed from its position in the frame (i.e., the frame is disassembled to a certain degree) or a similar joint is tested instead of the actual joint. Continuing the example of bonded joints in aircrafts, many governmental airline agencies, such as the Federal Aviation Agency (FAA) in the United States, require periodic maintenance checks to ensure the safe operation of all the aircrafts within their jurisdictions. For example, ‘C-checks’ and ‘D-checks’ are maintenance checks that are required by the FAA every few years on airplanes in the United States and such checks often require joint testing and joint inspection. Because conventional joint testing systems and methods are performed ex situ, these checks often involve substantial cost and expense as the testers have to disassemble large portions of the aircraft. In other words, conventional testing systems and procedures are not well suited for testing the strength of joints in situ. Additionally, conventional testing systems also involve visually detecting cracks, defects, or other visible evidences of failure.